Rig walking system with cantilever-mounted lifting jack assemblies

ABSTRACT

A walking system for moving a load over the ground includes a substructure having laterally spaced-apart, rigidly interconnected main beams for carrying the load above the ground. A jack support beam is mounted as a cantilever on top of each main beam on opposite ends thereof, and each includes a lifting jack assembly. Each lifting jack assembly includes a power-driven hydraulic cylinder having a ram with a foot plate, and each is selectively operable for extending a ram downwardly to force the foot plate against the ground to raise the substructure off the ground, and for retraction to disengage the foot plates from the ground, thereby lowering the substructure to the ground. Each jack lifting assembly further includes a shifter mechanism selectively operable for displacing the main beams and the substructure along the ground in a selected steering mode when the lifting jack assemblies have been actuated to raise the main beams and the substructure above the ground.

BACKGROUND OF THE DISCLOSURE

The present disclosure is directed to walking systems, large machinesoperable for transporting massive and heavy loads, upwards of thousandsof tons, over a surface area, such as the ground, snow, gravel or sand,etc. Walking systems are designed as non-wheeled power-driven vehiclesfabricated from iron and steel. They find particular utility in carryingand sequentially transporting huge structures such as oil drilling rigsand their support or service modules to pre-drilled, ground-installedconductor pipes. This is done prior to drilling well bores in fieldsundergoing oil exploration, or over existing well bores inpreviously-worked old fields, or the like.

The present disclosure is directed to a walking system and itssubstructure for transporting heavy machinery or equipment from onelocation to another, and more particularly to a walking system which canbe moved along a straight line or also steered. The walking system canbe steered so that it is displaced to align or orient equipment such asa drilling rig, precisely above a well bore, or move to another areaentirely.

EXAMPLES OF PRIOR ART WALKING MACHINES AND SYSTEMS

There are numerous examples of walking machines and systems which havebeen designed for use in moving drilling rigs for positioning over wellbores during oil exploration. An example of a known walking machine isdisclosed in U.S. Pat. No. 6,581,525 where a load-carrying transportapparatus for moving a heavy load, such as an oil drilling rig, over asurface includes a substructure for carrying the load, a track memberpositioned on the surface adjacent the substructure and a plurality oflift assemblies mounted on the substructure selectively operable forextension toward the surface to engage the track member and raise thesubstructure above the surface so that it is carried on the trackmember. The lift assemblies are also operable for retraction to lowerthe substructure onto the surface.

A shifter mechanism disposed adjacent to the substructure and the trackmember is selectively operable for displacing the substructure along thetrack member when the lifting assemblies have been extended toward thesurface to raise the substructure above the surface. The shiftermechanism is also operable for displacing the track member on thesurface relative to the substructure when the lifting assemblies havebeen retracted and disengaged from the track member. The track member isdimensioned to provide a steering area and at least one of the liftingassemblies is selectively positionable to a predetermined angle within arange for moving in the steering area along the track member so that theload-carrying apparatus can be steered along a selected direction.

Another example of a walking machine is disclosed in U.S. Pat. No.5,921,336 in which a drilling rig substructure is provided with aplurality of lifting jacks, and each lifting jack is connected to a jackpad. Roller assemblies are mounted at the lower end of the lifting jacksand each jack pad has a center beam that the roller assemblies engage.The jack pads are rotatable in 360° about a vertical axis. A push-pullmechanism extends between each jack pad and each roller assembly to movethe rollers horizontally in relation to the jack pad. In operation, whenit is desired to move to a well bore, the lifting jacks are extended,forcing the jack pad against the ground.

Continued extension causes the upper end of the lifting cylinder toraise the substructure and accompanying drilling rig to move from groundlevel. The lifting jacks now remain in the extended position and thepush-pull mechanisms are then actuated to move the substructure in agiven direction. The lifting jacks are then retracted so that thesubstructure returns to the ground and the jack pad is then raised andmoved to a new position.

A further example of the prior art is U.S. Pat. No. 7,819,209 whichdescribes a guided transport unit for moving a superstructure in angularmovements over a surface. There is disclosed a skid pad, a verticaldisplacing member engaged with the skid pad, a base operativelyassociated with the vertical displacing member, and a directionalactuator. The base includes a planar element for engaging the surfaceover which the superstructure is transported, and a carrier for movingthe vertical displacing member and skid pad relative to the surface. Thedisclosure shows that the side walls of the skid pads are provided withopenings to enable the guided main structures to pivoted to extend atleast partially outside of the skid pads.

SUMMARY OF THE DISCLOSURE

The present disclosure is directed to a walking system and itssubstructure for transporting heavy machinery or equipment from onelocation to another, and more particularly to a walking system which canbe moved along a straight line or also steered. The walking system canbe steered so that it is displaced to align or orient equipment such asa drilling rig, precisely above a well bore, or move to another areaentirely.

As noted above, the present disclosure is directed to a walking systemfor moving a load over the ground constructed as a substructureincluding a pair of spaced-apart, rigidly interconnected main beams,often referred to as “skids.” The main beams form the lower part of thesubstructure, and the entire arrangement may be raised above the groundand transported, carrying the load, in a preselected or given directionby means of a plurality of lifting jack assemblies.

The present disclosure contemplates such a walking system in which ajack support beam is mounted on top of each main beam on opposite endsthereof, and a lifting jack assembly is mounted on each jack supportbeam to extend downwardly therefrom. Each lifting jack assemblyincorporates a power-driven hydraulic cylinder having a ram with aground-engageable foot plate. The power-driven cylinders are selectivelyoperable for extending their associated rams downwardly to force thefoot plates against the ground to raise the substructure as a unit offthe ground. The power-driven cylinders may be actuated to retract theirrams to disengage the foot plates from the ground, thereby lowering thesubstructure onto the ground. A shifter mechanism is mounted on eachlifting jack assembly selectively operable for displacing thesubstructure along the ground when the power-driven cylinders have beenactuated to extend the rams to raise the substructure above the ground.

In accordance with the disclosure presented here, each jack support beammounted on a main beam includes an extended end or outboard sectionprojecting outwardly from the end of its associated main beam. Theoutboard section is arranged for supporting a lifting jack assembly inits entirety, including its power-driven cylinder, ram, foot plate andshifter mechanism outwardly from the end of its associated main beam.This is accomplished by designing each jack support beam to be mountedas a cantilever on its associated main beam. Further, this constructionenables the outboard section to be inclined relative to the long axis ofthe main beam-mounted jack support beam.

The service module, supported on a substructure separate from that ofthe drilling rig, provides the necessary auxiliary equipment for thedrilling rig. This equipment includes engines, pumps, motors, pipestorage, fuel, and mud pumps, to name a few, necessary for operating thedrilling rig. The service module is interconnected with the necessaryhoses, pipes, electrical conduits, etc. to the drilling rig. The servicemodule and drilling rig each have an operator's cab, so that theoperators of these two massive modules can control the necessarypositioning of their respective substructures and loads. The drillingrig and service modules can together weigh upwards of 4-5,000 tons.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a walking machine or systemillustrating one of the main beams supporting the substructure, and alsoshows a pair of lifting jack assemblies and associated jack supportbeams mounted on the left and right sides of the main beam, each withtheir foot plates raised off the ground, so that the entire weight ofthe main beams and substructure with associated load is borne on theground;

FIG. 2 is a top plan view of the walking system of FIG. 1, with thesubstructure deleted to show the two laterally spaced-apart main beamsand their associated lifting jack assemblies and jack support beams, thestructural interconnection between the two main beams not beingillustrated;

FIG. 3 is an enlarged side view of the lifting jack assembly and jacksupport beam shown on the left in FIG. 1;

FIG. 4 is a top plan view of the lifting jack assembly and jack supportbeam shown in FIG. 3;

FIG. 5 is a side view, taken along section A-A of FIG. 4, with portionscut away to show details of the lifting jack assembly and jack supportbeam shown in FIG. 3; and

FIG. 6 is a view, taken from the left and looking toward the liftingjack assembly and jack support beam shown in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As stated at the outset, the present disclosure is generally directed toa walking system for moving a load over the ground, and is constructedas a substructure supported by two main beams. As shown in the side viewof FIG. 1, a walking system is generally indicated at 10, and includes asubstructure 12 supported by a pair of spaced-apart, rigidlyinterconnected main beams 14 and 16, commonly referred to as “skids.”The main beams form the lower part of the substructure, and are rigidlyinterconnected by a network of support struts or cross members, whichare not shown in FIG. 2. Substructure 12 includes spaced-apart uprightsupports, two of which are illustrated at 18 and 20 to bear the weightof a platform 22 and its load which may be a drilling rig or servicemodule having support equipment, neither shown here. Uprights 18 and 20are pivotally connected at 18 a and 20 a, respectively, to platform 22and pivotally connected at 18 b and 20 b, respectively, to main beam 14.

While not shown in either FIG. 1 or 2, there are two uprights positionedbehind those shown at 18 and 20, which are pivotally connected toplatform 22 and main beam 16, similar to how uprights 18 and 20 aremounted. A diagonal brace or strut, shown at 24, is pivotally connectedat 24 a and 24 b, to platform 22 and main beam 14, respectively. Strut24, plus another one hidden from view in FIG. 1 pivotally connected toplatform 22 and main beam 16, can be interlocked to hold platform in itsupper, deployed position, as shown in FIG. 1. Both struts may beactuated to be swung or pivoted downwardly to lower platform 22 to lieagainst main beams 14 and 16, when desired.

A plurality of steerable lifting jack assemblies are operable forlifting the main beams and substructure and raising them with theircorresponding loads above the ground, and for lowering them as well. Theentire substructure, main beams inclusive, may be raised above theground and transported, carrying the load, in preselected or givendirections by means of the lifting jack assemblies, which are indicatedgenerally at 26 and 28 mounted on main beam 14, and 30 and 32 mounted onmain beam 16 (see FIG. 2). Because each lifting jack assembly isessentially the same, reference will be directed to principally to theconstruction of lifting jack assembly 26 shown mounted on the left endof main beam 14, and also shown in the enlarged views of FIGS. 3-6. Aswill become apparent, the lifting jack assemblies are mounted incantilever fashion so they are positioned away from or just outside ofthe ends of an associated main beam.

Lifting jack assembly 26 is mounted on a jack support beam 32 to extenddownwardly from an extended end or outboard section 34 of support beam32 to project outwardly from the end of its associated main beam, suchas main beam 14. The combination of the support beam and the jacklifting assembly functions as a lifting mechanism, as will be described.The outboard section is constructed for supporting lifting jack assembly26 in its entirety so all the components making up the lifting jackassembly are spaced outwardly from the end of the main beam alignedalong its longitudinal axis. This is accomplished by mounting supportbeam 32 as a cantilever beam on main beam 14 with its outboard sectioncreating a moment about the pin connections, shown at 33 and 35. Themanner of installing the pin connectors will be described later. Theoutboard section is inclined relative to the long axis of the main beamand the jack support beam.

Lifting jack assembly 26 incorporates a power-driven hydraulic cylinder36 operable for extending and retracting a ram 38. Mounted on the end ofram 38 is a foot plate assembly, generally indicated at 40, and a rollerassembly 42 is mounted on the end of the ram engaging the top surface ofa ground-engageable foot plate 44, enabling relative travel (see FIG. 5)between ram 38 and foot plate 44. A steering mechanism, which mayinclude a sector plate of conventional design, generally shown at 46,can be selectively rotated to pivot ram 38 and foot assembly 40 and fixit at a selected angular orientation about a vertical axis which extendsthrough the center of cylinder 36 and ram 38. Any one of six differentsteering modes may be selected, as will be described.

All four of the power-driven cylinders are selectively operable forsimultaneously extending their associated rams downwardly to push thefoot plates against the ground to raise the main beams and substructure22 as a unit off the ground. The power-driven cylinders may be actuatedto retract their rams to disengage the foot plates from the ground,thereby lowering substructure 22 onto the ground. A pair of shiftermechanisms are mounted on each lifting jack assembly, each with its ownhydraulic travel cylinder and rod arrangement. As shown in FIG. 3, ashifter mechanism 48 and another opposite it indicated at 50 in FIG. 6have been actuated to retract their rods, and guide bars are shown at 52and 54.

The shifting mechanisms may be operated to extend their rods, so that inthe view of FIG. 3 foot plate 44 would be shifted to the left. All theshifter mechanisms are operable in sequence with one another. Thus itcan be seen that the shifter mechanisms are selectively operable forsimultaneously displacing their associated foot plates relative to theirsupport beams and main beams. This can only be done when the foot platesare elevated above the ground. (A hydraulic power unit or HPU is showngenerally, but all hoses, controls, valves, etc. are not shown as theyare conventional.)

As shown in the top plan view of FIG. 4 and the section view in FIG. 5,taken along lines A-A of FIG. 4, support beam 32 and its extended endsection 34 are formed as a unitary box beam mounted to its associatedmain beam 14 by detachable pin connectors 33 and 35. Side walls formedof plate material are shown at 56 and 58, a top plate at 60 and a bottomplate at 62. Examples of a plurality of transversely extendingstiffening members are shown at 64 and 66. Outboard section 34 includesan upper surface defined by an inclined plate 68 provided with anopening 68 a, enabling access to an internal, transversely-extendingmounting plate 70 to which hydraulic cylinder is rigidly connected bymeans of a plurality of bolts 71.

Mounting of the Cantilevered-Supported Lifting Jack Assemblies

The method of mounting the jack support beams and their associatedlifting jack assemblies onto a main beam is straight forward andefficient, and is accomplished generally in the following fashion, withattention directed to jack support beam 32 as an example. Initially,jack support beam 32 is fabricated but is not connected with itspreassembled, corresponding lifting jack assembly, such as that shown at26. A crane is attached to the eyelets or “pick points” shown at 72 and74 secured on the top of the jack support beam, and lifts the unit intoposition above a receiving main beam such as that indicated at 14 toalign holes in brackets or lugs 76 and 78.

These holes are shown at 76 a and 78 a, respectively, and they are to bealigned with corresponding holes in lugs 41 and 43 (see FIG. 1)previously welded into position on main beam 14. (There arecorresponding lugs, not shown, on the other side of main beam 14.) Itwill be noted that lugs 76 and 78, and their counterparts 77 and 79 onthe opposite side, are spaced from their sidewalls, enabling them toslip over the corresponding lugs on main beam 14 for determiningalignment, necessary for receiving pin connectors 33 and 35. Lugs 78 and79 may be thought of as “connection lugs,” and may be tacked intoposition, initially, and may have to be moved and retacked intoposition, prior to final welding into place, after proper alignment hasbeen determined. Once proper alignment has been determined, jack supportbeam 32 is lifted away, and connection lugs 78 and 79 are welded intotheir correct positions.

With the lugs now in properly aligned position, the jack support beam islowered onto the lifting jack assembly which has been placed on asupport, such as the ground. Lowering continues until the bottom ofmounting plate 70 engages the top of power-driven cylinder 36. At thisjuncture, bolts 71 are attached to interconnect power-driven cylinder 36to mounting plate 70, completing the mounting of jack support beam 32onto lifting jack assembly 26. This entire unit now can be lifted by thecrane into position on top of main beam 14, and shifted until the lugson the jack support beam are realigned with the lugs on the main beam.The pin connectors are now driven in, and the support beam and liftingjack assembly are now fully installed. This is the general method of howeach of the four jack lifting assemblies are mounted on the jack supportbeams with the resulting unit then being attached to a main beam.

The walking system of the present disclosure is designed to enablesteering, while the load is distributed over the ground, in a selectedone of multiple modes, namely, longitudinal steering, simple steering,transverse steering, complementary steering, crab steering and circularsteering. To implement the orientation necessary for each of thesesteering or traveling modes, the lifting jack assemblies must be raisedso that their foot plates disengage from the ground. In this positionthe main beams and substructure and load will be entirely supported onthe ground, with bearing pressure applied downwardly through the mainbeams onto the ground Next, the lifting assemblies are actuated toorient the foot plates in the desired steering mode, i.e., longitudinalsteering, simple steering, etc.

In the next step the lifting jack assemblies are actuated to extend therams downwardly to position the foot plates so that they engage theground. Further extension of rams downwardly raises the main beam, andthe entire weight of the main beams, substructure and load, be it from adrilling rig, or service module is now transferred directly onto theground through the foot plates.

In this position, with the mode of steering having already beenpredetermined, the travel cylinders are actuated simultaneously as agroup to displace or shift the main beam, the substructure and loadrelative to the foot plates, all of which remain stationary. When thetravel or displacement has been completed, the jack lifting assembliesare actuated to lower the main beams onto the ground, and furtherretraction frees the foot plates from engaging the ground. The sectorplate of the steering assembly may be selectively repositioned in thesteering mode anticipated for the next direction that the walking systemwill take. And after operations, such as drilling, etc. have beencompleted, the lowering of the repositioned foot plates may begins andthe process repeated.

From the above description, it should be appreciated that the presentdisclosure provides a walking system enabling heavy loads to be readilydisplaced and precisely turned to be positioned over a relatively smallarea, such as a conductor pipe at an oil drilling site. An advantageresides in the relatively simple construction which providessubstructures for carrying and transporting a pair of loads, such as adrilling rig and a service module.

Still a further advantage in the present invention resides in thespecific construction of the jack support beam, formed as a cantileverwith an extended end or outboard section for mounting a lifting jackassemble and its associated foot plate close to, but away from the endof a main beam or skid. In this position, the foot plate has room to bepositioned in a preselected steering mode, when the foot plate has beenraised above the ground. The jack support beapa steering system whichenables a pair of heavy loads, such as a drilling rig and a servicemodule, to travel in a selected direction with the relative positionssubstantially maintained. This finds particular importance because thedrilling rig and service module have interconnected equipment; theservice module provides electricity, a source of mud for the drilling,gas, etc. to the drilling rig, and these connections must be maintainedduring transport of the respective substructures. The simplicity of thesubstructures, which includes the main beams, the lifting assemblies,the sub beams and the steering mechanisms, enables the relativepositioning to be maintained, both in straight line travel and travel inwhich the units are steered.

We claim:
 1. A walking machine for moving a load over the groundcomprising: a substructure having first and second main interconnectedmain beams for carrying the load above the ground; a first liftingassembly mounted adjacent a first end of each main beam including apower-driven cylinder connected to a plunger element with a foot plate,a second lifting assembly mounted adjacent an opposite, second end ofeach main beam including a power-driven cylinder connected to a plungerelement with a foot plate, wherein each power-driven cylinder isselectively operable for extending its plunger element downwardly toforce its foot plate against the ground to raise the substructure offthe ground, and for retraction to disengage its foot plate from theground, thereby lowering the substructure to the ground; a first shiftermechanism mounted on each first lifting assembly; a second shiftermechanism mounted on each second lifting assembly; each first shiftermechanism being selectively operable for simultaneous extension andretraction in opposition to one another to displace the main beam andthe substructure along the foot plates in a selected steering mode whenthe lifting assemblies have been actuated to raise the main beams andthe substructure above the ground.
 2. The walking system of claim 1wherein each support beam includes an extended end projecting outwardlyfrom the end of its associated main beam, the extended end arranged forsupporting a lifting jack assembly so that an associated foot plate isspaced outwardly from the end of its associated main beam.
 3. Thewalking system of claim 2 wherein each support beam is mounted as acantilever beam on its associated main beam so that the extended end isinclined relative to the long axis of the support beam mounted on themain beam.
 4. The walking system of claim 3 wherein the support beam andits extended end are formed as a unitary box beam mounted to itsassociated main beam by detachable pin connections, wherein the extendedsection is provided with an internal, transversely-extending mountingplate for connection to an associated hydraulic cylinder; and whereinthe extended end section includes an upper surface provided with anopening enabling access to the mounting plate and its associatedhydraulic cylinder.
 5. A lifting mechanism for mounting on a main beamof a walking system substructure to facilitate selective raising andlowering of the substructure relative to the ground comprising: asupport beam for mounting on top of a main beam adjacent an end thereof;a lifting jack assembly for mounting on the support beam including apower-driven hydraulic cylinder having a ram with a foot plate, whereinthe power-driven cylinder is selectively operable for extending andretracting the ram and foot plate; and a shifter mechanism mounted onthe lifting jack assembly selectively operable for displacing the footplate relative to the support beam.
 6. The lifting mechanism claim 5wherein each support beam includes an extended end dimensioned toprojecting outwardly from the end of a main beam to which it is to bemounted, the extended end arranged for supporting a lifting jackassembly so that an associated foot plate is spaced outwardly from theend of its associated main beam, when so mounted.
 7. The liftingmechanism of claim 6 wherein each support beam is dimensioned to bemounted as a cantilever beam on a main beam so that the extended end isinclined relative to the long axis of the support beam when mounted onthe main beam.
 8. The lifting mechanism of claim 7 wherein the supportbeam and its extended end are formed as a unitary box beam for mountingon a main beam by detachable pin connections, wherein the extendedsection is provided with an internal, transversely-extending mountingplate for connection to the hydraulic cylinder; and wherein the extendedend section includes an upper surface provided with an opening enablingaccess to the mounting plate and the hydraulic cylinder.
 9. A method forinstalling a lifting mechanism having a jack support beam and a liftingjack assembly onto the main beam of a walking system, wherein thewalking system includes a substructure having laterally spaced-apart,rigidly interconnected main beams; comprising: lifting the jack supportbeam and placing it on top of a selected main beam of the walkingsystem; moving the jack support beam into a position adjacent mountinglugs on the main beam and determining if mounting lugs on the jacksupport beam are aligned therewith; adjusting the position of mountinglugs on the jack support beam, if necessary; welding the mounting lugson the jack support beam into aligned position; lifting the jack supportbeam into position above the jack lifting assembly and attaching themtogether as a unit; lifting the jack support beam and attached liftingjack assembly as a unit into position on top of the main beam; andaligning and connecting the lugs on the jack support beam with the lugson the main beam.